The usefulness and need for silver ion antimicrobials
BY STEVE MCINTOSH
Special to The Wholesaler
Silver has been used for centuries to reduce bacteria. From the ancient Egyptians lining urns with silver to maintain the freshness of drinking water, to babies “born with a silver spoon in their mouths” to ward off the plague, silver has long been recognized as a valuable tool. In recent years, silver ion-based antimicrobial materials have been incorporated into products ranging from medical devices to faucets to drains and P-traps, all with demonstrated efficacy in active reduction of bacteria on surfaces. A recent clinical study demonstrates the dangers that lurk from the improper design of healthcare environments. A study of another type shows how well silver ion-treated products work in reducing bacteria in healthcare environments. Important conclusions can be drawn from both studies.
Deaths caused by infections resulting from environmental bacteria were the subject of Outbreak of Multidrug-Resistant Pseudomonas aeruginosa Colonization and Infection Secondary to Imperfect Intensive Care Unit Room Design (1). During the time span of December 2004 through March 2006, 36 patients in the intensive care and transplant units of Toronto General Hospital developed Healthcare Associated Infections (HAIS) that were a result of Pseudomonas aeruginosa exposure. Twelve of the patients died as a direct result of the infection. A great deal of detective work went into solving the mystery of the source of the infections. The ultimate source of the bacteria was Pseudomonas biofilm growth in the P-Traps and drains in handwashing sinks. The handwashing facilities had a faulty design. The sinks had shallow basins and faucets with gooseneck spouts. When water from the spouts splashed directly onto the drains, bacteria laden water splashed out of the basins, and onto countertops directly adjacent to the patients’ heads. Use of the handwashing sinks was suspended, and measures were taken to disinfect the sinks, faucets, drains and P-traps, and countertops. While the sinks were not in use, the infections subsided. Despite the disinfection efforts, the drains and P-traps became recolonized. The outbreak did not end until the sinks were modified with spouts that did not flow directly into the drain, eliminating splashing water.
The January 2009 issue of the Journal of Infection Prevention published a clinical study titled Reduction of Bacterial Contamination in a Healthcare Environment by Silver Antimicrobial Technology (2). A major acute care facility that is part of the National Health Service in the United Kingdom recently completed a study and published the results, comparing the differences in bacteria levels between rooms with silver ion-treated surfaces, and control rooms with untreated surfaces. All rooms that were part of the study were renovated. The study rooms contained silver ion-treated products, while control rooms contained untreated products. Products that were treated with silver ion antimicrobial material included water faucets, door hardware, cubicle curtains, coated wood products and furniture. Bacteria levels were tested for four months, comparing the bacterial colonization levels between the two groups of rooms. There were two findings from the study. First, the bacteria levels in the study rooms, with silver ion treated products, had a mean reduction in bacterial counts of 95.8%. The second finding was that untreated products in the study rooms that contained treated products had a mean reduction in bacteria levels of 43.5% . The suggestion is that because other products in the room utilize antimicrobial material, there are fewer bacteria available for cross contamination to the untreated products.
What can be taken from these two clinical studies? The relationship between bacteria in the healthcare environment and infections is being more thoroughly studied and understood. The incident at Toronto General Hospital proves that environmental bacteria can lead to infections and deaths. Other studies have shown the same thing. If a patient in a hospital room has an infection from resistant bacteria, such as mrsa or vre, subsequent patients in the same room have a higher incidence of the same infection (3). Dr. Andrew Simor from Toronto’s Sunnybrook Health Sciences Centre suggested two issues from the outbreak of Pseudomonas infections. First, that attention should be given to the design and location of handwashing facilities. Dr. Simor goes on to say that, “hospitals can’t prevent biofilms from forming in sinks, despite their best efforts” (4). The study regarding the effectiveness of silver ion-based antimicrobial materials suggests otherwise. When products utilizing silver ion technology are introduced to the healthcare environment, bacterial colonization is shown to be reduced.
It is not currently possible to prove whether or not saniguard® treatment, a silver ion based material, has a direct correlation to infection rates, nor is any health claim of this sort being made. Antimicrobials are not the same as disinfectants, but a double standard exists in the selection of products used in healthcare settings. Proof of a direct correlation between infection rates and antimicrobial products is demanded by healthcare professionals. The same requirements are generally not made when selecting traditional disinfectant sprays. The only proof that is typically necessary for a disinfectant is that it meets the standard of killing 99.9% of particular bacteria within a certain time frame. A clinical study of individual products, with a direct link to infection rates, is not required. Saniguard treatment has been shown in independent lab testing (data available) and evidence-based field testing (5) to actively reduce bacteria on surfaces. Testing also suggests that silver ion-based materials are effective in preventing the growth of biofilms. While saniguard treatment is not a replacement for hand washing and everyday hygiene, it can act as an extra tool in the efforts to reduce environmental bacteria. Eventually studies will be undertaken in an effort to correlate reductions in infection rates with the use of products containing antimicrobial treatments. Bacterial resistance is extremely rare with silver ions, and there are no adverse health effects from the levels of silver ions that are released. The prudent answer is to use the measures that are available to reduce bacteria levels on surfaces.
Products from the members of the saniguard Alliance utilize coatings and polymers containing silver ions. Members of the saniguard Alliance include chg (faucets, showers and plumbing hardware, Colonial Bronze (cabinet hardware), Elcoma (grab bars), Great Grabz (decorative safety bars and bath accessories), Leonard Valve (shower valves), McGuire (drains and P-traps), Praxis Companies (Comfort Designs brand shower and bath units), Sloan Valve (flush valves and bedpan washers) and TownSteel (door hardware). More information is available at www.saniguardalliance.com.
Steve McIntosh is national manager with Component Hardware Group. Chg is a leading designer, manufacturer and distributor of premium plumbing and hardware products for the foodservice, institutional, healthcare and commercial markets. Based in Lakewood, N.J., they can be reached at 800/526-3694 or on the web at www.saniguard-online.com.
1. Outbreak of Multidrug-Resistant Pseudomonas aeruginosa Colonization and Infection Secondary to Imperfect Intensive Care Unit Room Design, Susy Hota, MD; Zahir Hirji, MHSc; Karen Stockton, MHSc; Camille Lemieux, MD, LLB; Helen Dedier, MLT; Gideon Wolfaardt, PhD; Michael A. Gardam, MD, MSc, Infection Control and Hospital Epidemiology, January 2009, vol. 30, no. 1
2. Reduction of Bacterial Contamination in a Healthcare Environment by Silver Antimicrobial Technology, L. Taylor, P. Phillips, R. Hastings, Journal of Infection Prevention January 2009, Vol. 10, No. 1
3. Risk of Acquiring Antibiotic-Resistant Bacteria From Prior Room Occupants, Susan S. Huang, MD, MPH; Rupak Datta, BS; Richard Platt, MD, MS, Arch Intern Med Vol. 166, Oct. 9, 2006
4. Sink, the Culprit Behind Infection Outbreak; Gooseneck faucets, shallow sinks behind deadly hospital infection outbreak Canadian Press, December 2008
5. Antimicrobial Facility Plumbing and Hardware is Put to the Test, Barbara H. Hornaday, MA, Infection Control Today, June 2008 Hardware i